write.arcGrid {pgirmess}R Documentation

Writes an ArcInfo ASCII grid from a matrix or data frame, with x, y, z values.

Description

Writes an ArcInfo ASCII grid from a matrix or data frame, with x, y, z values

Usage

write.arcGrid(xyz, file, zcol = 3, xcol = 1, ycol = 2, NODATA = -9999)

Arguments

xyz a matrix or a data frame with x, y, z values
file a character string naming the file to write to
zcol the column number for the z-axis
xcol the column number for the x-axis
ycol the column number for the y-axis
NODATA the value for no data

Details

A "gap stopper" function that can be used eg to export 2D kernel densities or any object for which a raster representation make sense. Such file can be imported on-the-fly from FWTools (Open Source GIS Binary Kit for Windows and Linux) <http://fwtools.maptools.org/>, if no data is a number. This plateform can export to Gtiff format readable with ArcGIS. The ESRI ArcToolBox does not read the "ArcInfo ASCII grid file" for some reasons.

Value

An ArcInfo ASCII grid file

Author(s)

Written by Roger Bivand for his students based on code by Edzer Pebesma.

Examples

library(splancs)
data(bodmin)   
mykernel<-kernel2d(as.points(bodmin), bodmin$poly, h0=2, nx=100, ny=100)
attributes(mykernel$z)<-NULL
mykernel$z[is.na(mykernel$z)]<--9999
mydata<-cbind(expand.grid(mykernel$x,mykernel$y),mykernel$z)
write.arcGrid(mydata,file="mytextgrid",NODATA=-9999)

[Package pgirmess version 1.3.8 Index]